A new mandarin citrus Citrus reticulata hybrid is described. The new variety designated xe2x80x98KEDEMxe2x80x99 is desirable to the consumer because of its attractive orange-red color and to the commercial grower because of the early maturing of its fruit.
The present invention relates to a new and distinct variety of mandarin Citrus reticulata hybrid developed by inventors Aliza Vardi, Pinchas Spiegel-Roy, Avraham Elchanati, Ahuva Frydman-Shani and Hana Neumann in Bet Dagan, Israel from a selection of plants grown from irradiated buds of the cultivar xe2x80x98Rishonxe2x80x99.
Asexual reproduction by recognized grafting techniques of the new variety in Israel has shown that the new characteristics are stabilized and permanently fixed through successive propagation.
The objective in breeding the present new variety, known by the designate xe2x80x98KEDEMxe2x80x99 was to induce seedless varieties through mutation breeding in easy peeling varieties. In the spring of 1989, about 100 buds of an easy peeling mandarin cultivar, xe2x80x98Rishonxe2x80x99 (U.S. Plant Pat. No. 8,377), were irradiated at the Weizmann Institute of Science, Rehovat, Israel, by exposure to 3.5 kh of gamma radiation from a Co60 source (G.B. 150A, Atomic Energy of Canada). xe2x80x98Rishonxe2x80x99 was the result of a controlled pollination cross, made at the Volcani Center, Bet Dagan, Israel, in 1978 between xe2x80x98Templexe2x80x99 (Citrus temple Hort. ex Y. Tanaka) as a pollen parent and xe2x80x98Michalxe2x80x99 (unpatented) as a pollen parent. xe2x80x98Michalxe2x80x99 is a cultivar of Israeli origin believed to be a natural hybrid between two Citrus reticulata xe2x80x98Blancoxe2x80x99 cultivars.
Troyer nucellar rootstocks were bud grafted with the individual buds of irradiated xe2x80x98Rishonxe2x80x99 bud wood and labeled mV1. Six to nine months after grafting the irradiated budwood, individual buds from the mV1 plants were re-grafted on Troyer nucellar rootstocks to establish about 300 mV2 plants.
Field planting was established from container grown mV2 plants in the spring of 1991. The first fruits were observed in October 1995 and a second observation made in October 1997.
A selection designated 13/5/82 had medium size orange color fruit, was easy to peel and had few seeds. The selection was distinguished from xe2x80x98Rishonxe2x80x99 as having 0-5 seeds per fruit as compared with 5-11 seeds for xe2x80x98Rishonxe2x80x99 and having a lower pollen fertility of 72% compared with 95% for xe2x80x98Rishonxe2x80x99 when pollen grains were stained with acetocarmine.
The selection, designated xe2x80x98KEDEMxe2x80x99, is a new variety of mandarin citrus that has a fruit with few seeds and flowers having anthers bearing pollen with low fertility compared to the parent xe2x80x98Rishonxe2x80x99. Table 1 shows some of the characteristics of xe2x80x98KEDEMxe2x80x99 compared to the parent xe2x80x98Rishonxe2x80x99.
The tree shape is similar to that of xe2x80x98Rishonxe2x80x99. The tree is vigorous and has small thorns in the leafy part of branches, especially in the lower portion and on the lower part of fruit bearing branches. Main branches have an upright attitude and young shoots have no anthocyanin coloration at the tip.
The fruits of selection xe2x80x98KEDEMxe2x80x99 develop the exterior orange color very early in the season, beginning in October, while at the same time the exterior color of the fruits of xe2x80x98Rishonxe2x80x99 are green-yellow. The bearing of the tree is regular and the productivity is good, about the same as for xe2x80x98Rishonxe2x80x99. The canopy is moderately dense. The bark of the young shoots is initially smooth and green gradually turning into a smooth yellow-green.
The chromosome number of xe2x80x98KEDEMxe2x80x99 is diploid (2n=18) as is the chromosome number of xe2x80x98Rishonxe2x80x99.
The leaves of xe2x80x98KEDEMxe2x80x99 are similar to those of xe2x80x98Rishonxe2x80x99. They are lanceolate and sharp pointed, small to medium in size. Leaf blade is firm, without undulation and straight concave in cross section. Petioles are without wings or have rudimentary wings.
The characteristics of the flowering and the flower parts are similar to those of xe2x80x98Rishonxe2x80x99. Flowering for both occurs at the end of March or during the first half of April as measured in Bet Dagan, Israel. Both xe2x80x98KEDEMxe2x80x99 and xe2x80x98Rishonxe2x80x99 produce about the same number of flowers and flower drop for both occurs in April. Terminal flower buds have no anthocyanin coloration. Flowers are borne singly and have an average number of stamens (about 20) with complete style development. Anther color is yellow. About 72.5% of the pollen grains were stained with acetocarmine in a test conducted at the Agricultural Research Organization, the Volcani Center, as compared with about 95% staining for xe2x80x98Rishonxe2x80x99 pollen grain.
The fruit has few seeds, about 0-5, even when optimal pollination conditions are employed. This compares with about 5-9 seeds per fruit in xe2x80x98Rishonxe2x80x99. Except for color development, the fruit characteristics of xe2x80x98KEDEMxe2x80x99 are in the range of the parent cv. xe2x80x98Rishonxe2x80x99.
The fruit shape is oblate and small to medium sized. When 50 fruits were measured, the fruit had an average weight 79 grams, an average height of 51 mm, and an average diameter of 56.5 mm. The fruit occasionally has a short necked and a depressed distal end. The fruit surface is usually smooth with an orange color, RHS 25A on The Royal Horticultural Society of London Colour Chart, and bears an average number of conspicuous rind oil glands. Fruit ripening does not differ from outside of the canopy to the inside, but the fruit color of the outside canopy is a little brighter compared to the fruit color of the inside canopy. There is no persistence of the style and the areola is not completely developed. A navel is absent or very rare. The rind is thin and easy to peel.
The color of the albedo is white and the flesh is yellow-orange in color. The fruit contains 9-11 segments and is very juicy. The seeds are small, smooth and polyembryonic as are the seeds of the parent xe2x80x98Rishonxe2x80x99. The external color of the seeds is ivory when fresh and yellowish when dry. The internal seed coat is white and the cotyledons are greenish. Polyembryonic seeds are present. The seed size, shape and texture are similar to that of the parent xe2x80x98Rishonxe2x80x99. The fruit reaches maturity early or very early in the season as does xe2x80x98Rishonxe2x80x99, which in Israel is late September to October. The ripening of the fruit on the tree and within the fruit is uniform. Fruit remaining on the tree does not regreen. If there is a heavy crop and the fruits are not picked the following season, the tree may produce less fruit (becomes alternate bearing). Pre-harvest drop of both developed and undeveloped fruit is similar to that of the parent cv. xe2x80x98Rishonxe2x80x99.
The results of the test conducted Oct. 15, 1997 on juice of representative ripe fruit of the new variety were as follows:
Total soluble solids (TSS): 14.9%.
Acid content.xe2x80x941.02%.
TSS/acid ratio.xe2x80x9414.55.